JPH0591244A - Image sensor and information processing unit - Google Patents

Abstract

PURPOSE:To attain reading and reproduction of a picture with high gradation by forming a slit for forming an optical path between an optical system and a sensor so as to be an optical iris from the optical system toward the sensor. CONSTITUTION:A light from a light source 3 is reflected in an original 8 and formed to a sensor 4 by a short focus image forming element array 2. Through the constitution above, a slit 5 between the image forming element array 2 and the sensor 4 is formed by processing a frame 1 to be a slit with a step difference. Then the slit interval is formed wide toward the optical system and narrow toward the sensor 4. Thus, a stray light is considerably reduced thereby preventing the stray light from being formed to the sensor 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image sensor and an information processing apparatus using the same.

[0002]

2. Description of the Related Art Conventionally, in an image sensor, light (stray light) other than the regular reflected light from a position on an image to be read, for example, reflected light from a position other than the reading position is incident on a light receiving element. In some cases, the reading accuracy of the image sensor is lowered and the read image is adversely affected.

In particular, in such a conventional example, when reading a document with multiple gradations, stray light enters the sensor, and it is not possible to accurately represent the light and shade. For example, when reading black information at a position on a document where an image is represented by black on a white background, even white information on the background around the black should enter the sensor as stray light and be read as black. The information was sometimes judged to be gray.

For example, as shown in FIG. 5, in a contact type image sensor using an image forming element array 2 such as a gradient index rod lens array as an optical system, a short focus image forming element array 2 and a light receiving element array are used. A frame 1 provided to form an optical path with (hereinafter referred to as a sensor) 4
Stray light a enters the upper slit (groove) T, is reflected here and enters the sensor 4, and this is a factor that adversely affects the image.

As a countermeasure against this, conventionally, the groove T is widened, or blackened in order to reduce the reflectance of the inner surface of the groove.

Alternatively, as shown in FIG. 6, a black tape (or a black printing portion or the like) 7 is arranged on the inner surface of the cover glass 6 on which the original is placed so that stray light does not enter the imaging element array 2. Was there. Or, as shown in FIG.
The black tape 9 was attached to the inner wall of the sensor zone E to prevent stray light from entering the sensor zone E.

Further, electrical signal processing is used to determine that a certain level of gray is black.

[0008]

However, in the structure in which the width of the groove T is increased in FIG. 5 or the inner surface thereof is black, stray light can be reduced to some extent, but high gradation reading is required. Can not be an effective measure. The same applies when performing electrical signal processing.

Further, even if the black tape 7 is attached to the cover glass 6 as shown in FIG. 6, the effect is small. This is because in order to prevent stray light, it is necessary to attach the black tape to the limit of not blocking the effective light beam b for reading the document, but it is not possible to block the irradiation optical axis of the light source 3.

Further, in the structure shown in FIG. 7, it is technically difficult to dispose the black tape 9 accurately, and the manufacturing cost is significantly increased.

The present invention solves these problems, makes it possible to greatly reduce the incidence of stray light to enable high-gradation reading, and does not complicate the manufacturing process or increase the manufacturing cost. And to provide an information processing device.

[0012]

To this end, the present invention provides
A sensor for performing photoelectric conversion, an optical system for forming an image of a document surface on the sensor, and a member having a slit forming an optical path between the optical system and the sensor,
The slit portion of the member has a shape that forms an optical diaphragm from the optical system side toward the sensor side.

Further, the information processing apparatus of the present invention is characterized by comprising the image sensor and a document holding means for holding a document at a reading position by the image sensor.

[0014]

In the present invention, by providing a portion in which the slit spacing is wide on the optical system side and narrow on the sensor side, stray light can be significantly cut and stray light can be prevented from forming an image on the sensor. is there.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings.

1 and 2 respectively show an embodiment of the present invention. FIG. 1 is a side sectional view showing an internal structure of a contact image sensor according to an embodiment of the present invention, and FIG. FIG. 6 is an enlarged view of a slit portion according to the example of FIG. In each of these embodiments, the shape of the slit between the imaging element array as the optical system and the sensor is devised so that the slit spacing is wide on the optical system side and narrow on the sensor side.

More specifically, the embodiment shown in FIG. 1 is characterized in that the slit portion 5 between the short focus image forming element array 2 and the sensor 4 is formed by stepwise slitting the frame 1. ..

The image sensor of the embodiment shown in FIG. 2 is characterized in that the slit plate 5 is attached to the frame 1 to form the slit portion.

In these figures, 1 is a frame for mounting each part and forming a slit portion of each of the above shapes, and 2 is an image forming element such as a gradient index rod lens array for forming an image of an original on a sensor. An array 3, a light source for illuminating an original, 4 a sensor, 5 a stepped slit portion, 5'a slit plate (FIG. 2), 6 a cover for covering the inside of the image sensor and placing an original 8 thereon. It is glass.

Further, a is a stray light which should be essentially unnecessary, b is an incident light beam (a light beam which should be effective) which is an area where reflected light from the reading position on the document surface is imaged on the sensor 4,
t is the thickness of the stepped slit portion 5 and the slit plate 5, and is t = 0.2 mm in each embodiment.

FIG. 3 shows an example of the configuration of an electric circuit related to the light receiving element which constitutes the sensor 4.

Here, PS is a bipolar transistor corresponding to one pixel for reading, SW ₁ is an NMOS transistor as a switch means for resetting by connecting the emitter to the reference voltage source V _ES , and SW ₂ is the base with the reference voltage. A PMOS transistor as a switch means for connecting to the source V _BB for resetting, SW ₃ is an NMOS transistor as a switch means for signal charge transfer, and CT is a capacitive load for generating a signal voltage.

In such a structure, at the time of reset operation, a negative pulse voltage is applied to the gate of the PMOS transistor SW ₂ and the base is clamped to the voltage V _BB .

Next, a positive pulse voltage is applied to the gate of the NMOS transistor SW ₁ so that the emitter becomes the voltage source V _ES.
, A current flows between the base and the emitter, and photogenerated carriers remaining in the base disappear.

Next, during the storage operation, both the NMOS transistors SW ₁ and SW ₃ are turned off, both the emitter and the base are brought into a floating state, and the storage operation is started.

During the read operation, a positive pulse voltage is applied to the gate of the NMOS transistor SW ₃ to turn it on, the emitter and the capacitor CT are connected, and the signal voltage is read to the capacitor CT.

The basic structure of such an image sensor is described in US Pat. No. 4,686,554 issued to Omi and Tanaka of the inventor, in which a bipolar transistor is used in an output circuit including a capacitive load. Is described as a charge storage type high-sensitivity, low-noise photoelectric conversion device to which the emitter is connected.

FIG. 4 shows an example of a facsimile having a communication function as an example of an image information processing apparatus configured by using the image sensor according to this example as the sensor unit 100.

Here, 102 is a feeding roller as a feeding means for feeding the original 8 toward the reading position, and 1
Reference numeral 04 is a separating piece for surely separating and feeding the originals 8 one by one. Reference numeral 106 denotes a platen roller that is provided at the reading position with respect to the sensor unit 100, regulates the surface to be read of the document 8 and conveys the document 8.

In the illustrated example, P is a recording medium in the form of a roll paper, and image information read by the sensor unit or image information transmitted from the outside in the case of a facsimile machine or the like is reproduced here.

Reference numeral 110 denotes a recording head as recording means for performing the image formation, and various types such as a thermal head and an ink jet recording head can be used. The recording head may be a serial type or a line type. Reference numeral 112 denotes a platen roller as a conveying unit that conveys the recording medium P to the recording position of the recording head 110 and regulates the recording surface thereof.

An operation panel 120 is provided with a switch for accepting an operation input as an input / output means, a message, and a display section for notifying the state of the apparatus.

Reference numeral 130 denotes a system control board as a control means, which includes a control section (controller) for controlling each section, a drive circuit (driver) for the photoelectric conversion element,
An image information processing unit (processor), a transmission / reception unit, and the like are provided. 140 is a power supply for the apparatus.

As the recording means used in the information processing apparatus of the present invention, for example, US Pat. No. 1,723,129,
It is preferable that the representative configuration and principle of the specification be disclosed in Japanese Patent No. 4740796. According to this method, at least one of the electrothermal converters arranged corresponding to a sheet or a liquid path holding a liquid (ink) is subjected to a rapid temperature rise corresponding to recorded information and exceeding nucleate boiling. By applying two drive signals, thermal energy is generated in the electrothermal converter, causing film boiling on the heat-acting surface of the recording head, and as a result, one-to-one correspondence with this drive signal and It is effective because it can form bubbles. Liquid (ink) is ejected through the ejection openings by the growth and contraction of the bubbles to form at least one droplet.

Further, as the recording head 110, a full line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus can be used.
The form may be either a configuration satisfying the length by a combination of a plurality of recording heads as disclosed in the above specification or a configuration as one recording head integrally formed.

In addition, the recording head 110 may be of a serial type, and the form thereof is fixed to the apparatus main body, or is electrically attached to the apparatus main body by being attached to the apparatus main body or the apparatus main body. The present invention is also effective when a replaceable chip type that allows ink to be supplied from a printer or a cartridge type in which the recording head itself is integrally provided with an ink tank is used.

[0037]

As described above, according to the present invention,
Stray light can be prevented from entering the sensor, and only the necessary effective light rays can be taken into the sensor, so that the original can be read correctly and fine gradations can be expressed. This also enables high-gradation reading and image reproduction.

In addition, the conventional measures, that is,
It is not necessary to dye the inner wall of the slit black, attach a black tape to the inner surface of the cover glass, dye the inner wall of the sensor zone black, or add a circuit that performs electrical signal processing on the read signal. Moreover, the manufacturing process is not complicated and the manufacturing cost is not increased.

[Brief description of drawings]

FIG. 1 is a side sectional view of an image sensor according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a slit portion of an image sensor according to another embodiment of the present invention.

FIG. 3 is a circuit diagram showing a configuration example of an electric circuit related to a light receiving element applicable to the configuration of the image sensor of the present invention.

4 is a side sectional view showing an embodiment of the information processing apparatus of the present invention to which the image sensor shown in FIG. 1 is applied.

FIG. 5 is a side sectional view showing a conventional image sensor.

FIG. 6 is a side sectional view showing a conventional image sensor.

FIG. 7 is a side sectional view showing a conventional image sensor.

[Explanation of symbols]

 1 frame 2 imaging element array 3 light source 4 sensor 5 stepped slit part of frame 5'slit plate 6 cover glass 8 original document 100 sensor unit 106 platen roller 110 recording head 130 system controller board a stray light b effective ray PS bipolar transistor t step With slit and slit plate

Claims (6)

[Claims] 1. A member having a sensor for performing photoelectric conversion, an optical system for forming an image of an original surface on the sensor, and a slit portion forming an optical path between the optical system and the sensor. And an image sensor, wherein a slit portion of the member has a shape that forms an optical diaphragm from the optical system side toward the sensor side. 2. The image sensor according to claim 1, wherein the slit portion of the member is formed by subjecting an optical path forming portion of the member to a step slit process. 3. The image sensor according to claim 1, wherein the slit portion of the member is formed by attaching a slit plate to an optical path forming portion of the member. 4. The sensor has a bipolar transistor corresponding to one pixel for reading, an output circuit including a capacitive load is provided at an emitter of the bipolar transistor, and a photoelectrically converted signal is a voltage at the capacitive load. The image sensor according to claim 1, wherein the image sensor is read as. 5. An information processing apparatus comprising: the image sensor according to claim 1; and a document holding unit for holding a document at a reading position by the image sensor. .. 6. The information processing apparatus according to claim 5, further comprising a recording head that performs recording by ejecting ink using thermal energy.